Q141 / 150 · MHT CET 2019 (Shift 1) · Physics

A magnetizing field of 500 A/m produces a magnetic flux of 4×10-5 Wb in an iron rod of cross-sectional area 0.4cm2 . The permeability of the rod in W/b/A-m is

  • A
    4×10-6
  • B
    1×10-3
  • Correct answer
    C
    2×10-4
  • D
    3×10-5

Solution

Given, magnetising field, H = 5000 A/m
Magnetic flux, ϕ=4×10-5Wb
Cross-sectional area, A = 0.4 cm2=4×10-5m2
∴ Permeability of rod,
μ=BH=ϕAH∴ϕ=BA⇒B=ϕA
=4×10-54×10-5×5000=2×10-4WbA-m

Hence, the correct answer is option: 'C'.

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